Hydraulic remote control device



Ecc. 3, 1946. R. LUCIEN 2,412,053

HYDRAULIC REMOTE CONTROL DEVICE Filed June 19, 1944 I-nvnor lenef Lucien Patented Dec. 3, 1946 I et Mecanlqnes S. I. A. M., Fribourg, Swltxerland, a corporation of Switzerland Application .time 19, 1944, serial No. 540.91m

in Great Braam Maren 24,1943

2 claims. (ci. en -51) This invention comprises improvements in or relating to hydraulic remote control devices. It is an object of the invention to provide means for the remote control of hydraulic apparatus such as jacks, for example in aircraft, which combines the advantages of centralised supply and control with rapid operation and freedom from risk of breakdown on interruption of supply.

On aircraft, especially on large aircraft, or on installations of hydraulic apparatus in other connections where the parts to be controlled are remote from the point of control and from the pressure source, if promptitude and reliability of operation are required it is necessary to provide large-diameter piping which extends from the pressure-source to the apparatus in order that the low of liquid may be prompt and free. Furthermore it is ordinarily necessary to have the source of supply of high-pressure fluid located close to the point of control. The result is that the pipe-work is heavy. Moreover its diameter and length makes it vulnerable and damage at any place in the pipe-system is likely to throw the whole installation out of order. Finally, lthe pump ordinarily employed as the source of supply, must have an output fast enough to operate the apparatus at the desired speed.

It has been proposed to control hydraulic jacks on an aircraft from a central control station by control means having electrical transmission and to have the hydraulic installation located in close conjunction with theojacks. This reduces weight and vulnerability but involves complication by introduction of the electrical apparatus.

In order to ensure reliable extension of an un.. der-carriage irrespective of damage to pipe-work it has also been proposed in prior United States patent specification No. 2,001,620 to provide for movement in the direction of extension being ef fected by pressure supplied by an accumulator located close to the jack so that only retraction needs to be effected by liquid supplied from the pressure-source. Certain risks due to the possibility o f damage to the intermediate piping were thus obviated and the quantity of pipe-work was reduced, but still the flow of the fluid had to take place in the full volume necessary for operation, through a length of piping extending the whole way between the pressure-source, the point oi control and the Jack and the capacity of the pump and size and weight of the piping necessary had to be designed accordingly.

According tothe present invention a hydraulic system wherein the apparatus to be operated is located at a distance from a point of control and a branched pressure-line which serves them in 2 l from a pressuresource,lcomprises, in combination, an accumulator located close to the apparatus (Jack or other device) t0 be operated, op..

erating valve-means and connections between the i accumulator and said apparatus to enable the accumulator when charged to operate the jack under control of said operating valve-means, hy draulic remote-control actuating means for the' operating valve-means, including connections to the point of control, and a pressure-line from the pressure-source to the accumulator for charging the same.

In this way only the short connections between the accumulator and jack require to be of large size, the pressure-line and the connections to the lpoint of control may be small and light. The

pressure-source, such as a pump,4 may be of small capacity inasmuch as its function is to charge the accumulatcrs and not directly to operate the jacks or the like.

Where, as is usual, the apparatus to be oper ated comprises several distinct devices, a plurality of accumulators may be provided therefor with separate operating valve-means for each device all connected by hydraulic remote-control means` to the control point and the pressuresource may be connected to the accumulators'by common. y Y l Preferably when the hydraulic devices include a jack a hydraulically-controlled locking-device v may be provided for one endof the movement i or both ends of the movement) of the jack and the operating valve-means include. a connection to the locking device to unlock it when the valvemeans are operated to apply pressure to the jack to move it. I In this way the apparatus in the case of any failure in the pipe-work may be caused by the locking device to remain in the position in which it has already been set and may alsoXnot 'be disturbed in the event of any failure in the A supply pump. v

It will be appreciated that the small capacity required of the control connections permits the use of very light pipes and this results not only in a saving of weight, which is important in the case of aircraft, but also in a reduction of the risk of damage in combat, which is important in the oase of military services. Furthermore such piping is much more easily installed.

'I'he following is a description, by way of example, of one installation in accordance with the invention:

The accompanying drawing is a diagrammatic 3 representation of the parts of the system andof the interconnecting pipe-work.

'I'lie installation comprises a number of hydraulic jacks on an aircraft (of which one only is shown at II) connected respectively to the undercarriage framework for retracting the same, to bomb doors, to landing flaps and the like (not shown in the drawing) as may be desired. Closely associated with each jack, or with a group of jacks where several jacks are located close together, is a hydraulic accumulator I2 of sufficient capacity to operate the jack or jacks at least once in each direction. The accumulators are connected through non-return valves 3 by smallbore pipe-work I4, I5 with a central supply pump I6 located in a position where it can readily be driven. by one of the engines of the aircraft. This Apump may be of small capacity and will be required to runon load for a longer proportion of the working period than is usual with hydraulic pumps on aircraft, which is beneficial from theA point of view of the pump. The function of the pump is to charge the accumulators, which may be done slowly. It will be observed that thepipe |15 is branched at I 4 to the accumulator I2 and other branches will be provided to the other accumulators. The accumulators are connected each by a short pipe I1 and 21 of large bore to an operating valve (in two parts I8, I9) for each I jack and the operating-valves by similar pipes 2li and 2| to the jacks. Thus when the operatingvalves are, operated the Jack is operated rapidly, irrespective of the supply capacity of the pump.

Each end of the jack cylinder is connected by the pipes 20, 2| to a supply compartment 22 in the operating-valve casing. Through the supply compartment 22 there passes the hollow stem 23 of a lift-valve 24 the exterior of which passes through the walls oi the compartment with a fluid-tight fit. Outside the compartment is an admission chamber 25 which is spanned by a diaphragm 26 containing a seating for the head of the lift-valve and one of the supply connections 21 from the accumulator I2 enters the admission chamber. The hollow stem 23 has a port 28 connecting the interior of the stem with the admission chamber 25 below the diaphragm 25 so that if the valve 24 is lifted from its seating the pressure uid from the accumulator will enter the stem through the port. Another port 29 in the stem connects the interior of the stem with the supply compartment 22 which is connected to the jack by pipe 2|. Thus when the lift-valve 24 `of either valve I8 or I9 is raised from its seating, the end of the jack II which is connected to the compartment will receive fluid under pressure fr om the accumulator. The interior of valve Il' I9, of which only the exterior is shown, is similar to that of valve I8.

As above stated, the stem 23 of the lift-,valve passes right through the supply compartment 22 and out through the wall thereof onthe opposite side from the head ofthe valve. The end of the stem is open and carries a seating 30; Beyond the compartment the end of the stem projects into an exhaust cylinder 3I which is connected` by a port 32 to a drain pipe 33. In the .cylinder 3| works a tappet 34 which can be moved so that it engages the seating 38 around the end of the stem 23 and thereby seals the interior ofthe valve Jack and in the other direction allows the valve to seat and connects the jack through the supply compartment 22 and the interior of the valve stem 23 to the drain pipe 33.

Beyond the exhaust cylinder 3|, and axially in line therewith, isa larger actuating or motor cylinder 35 containing a relay piston 36. This piston may be broadly designated a valve-actuating motor. 'I'he relay piston 36 has a stem 31 which is capable of engaging the tappet 34 in the exhaust cylinder but is urged away therefrom by a spring 38. Behind the relay piston the operating cylinder is provided with a connection to a iinebore control-pipe 39 (or 40 as the case may be) and when pressure is applied in the operating cylinder 35 by uid supplied through the controlpipe 'the stem of the piston therein is urged against its spring 38 into contact with the piston or tappet 34 in the exhaust cylinder 3| and' thereby closes the piston against the lift-valve, and if the movement is continued lifts the liftvalve from its seating.

The two control-pipes 39, 40' which openinto the two actuating cylinders 35 are connected to a control-box in two parts 4|, 42 located in a lcen-I tral point of control on the aircraft where it can readily be controlled by the pilot or other personnel. Each control-box comprises a, lever 43, which lever operates control lift-valves 44, 45.

"I'he valves 44 admit hydraulic `fluid under pres- I sure from a compartment 46 to compartment 41 of the box, and thence to one of the control pipes 39 when one lever .43 is moved in one direction and the other controlpipe 48 when the other lever 43 is moved in the other direction.

`The levers 43 are linked by spindle 48 to move in unison and controlled by handle 49. The fluid under pressure is supplied to the control-box from the aforesaid central pump I8 by pipe 50 and only a very small quantity of fluid is necessary to operate the relay pistons and open the lift-valves of each jack. (It will be understood the cylinders 35, 3|, I8 and I9 and associated parts are not to scale and in practice are much smaller in proportion to the size of the other parts than is possible to show on the drawing.)

'I'he valves 45 when opened connect the compartments 41 to compartments 5| and the compartments 5I are connected to a drain pipe 52. The valve 45 in each box is opened by lever 43 when valve 44 is closed. 'I'he boxes 4I, 42 are reversed in relation to one another so that when pipe 39 is under pressure pipe 45 is open to drain, and vice versa.

A similar pair of control-boxes 4|, 42 and handle 4.9 is provided at the central station for each jack in the system and thus by a. system of very light pipe-work the connections of the Jacks to their respective accumulators can be controlled as desired and the jacks operated in either direction without necessitating the whole of the operating fluid iiowing all the way to the Jacks from the pump I6 during the period of operation.

Furthermore, some of the jacks, particularly theunder-carriage Jacks, may be provided with hydraulically-operated bolts 53, 54 or their equivaient for locking them in oneor other extreme of movement. These bolts are slidably mounted in stem from the drain, while further movement of the piston or tappet would lift the valve 24 from its seating. It will be appreciated therefore that movement of the actuating tappet 34 in one direction lifts the valve and applies pressure to the pistons and return springs. The cylinders which contain the bolt-withdrawing pistons are connected by short pipes 51, 58 to the actuating cylinders 35 which contain the relay pistons 35. The connections for this purpose extend to the centre of that end of the actuating cylinders to on the relay pistons 38 when the latter are fully` retracted under the iniluenoe o1' their springs 38 to allow the lift valves 2l to close. v

In operation, the first eiiect of admission' of. pressure to one of the actuating cylinders 35 is to move the relay piston 36 off the central seating 6U and to admit control iluid under pressure to one of the bolt-withdrawing'cylinders 55 or 58, as the case may be, sothat the jack is unlocked. After a. short movement of the relay piston the rod 31 engages the tappet 34 in the exhaust cylinder 3i oi' the valve and opens the lift-valve 24 to cause the jack to move. The other lift-valve in the other operating-valve casing i8 or i9, as the case may be, is, of course, at this time open to drain pipe 33. The jacks are thus locked in either of their end positions until the relay pistons are operated, whereupon they are first unlocked and then have pressure applied to them to tween said jack and said accumulator; operating ameter but is not under pressure and may be thin. Y

Also only one such pipe is required and if ruptured it does not lead to any failure of operation, only loss of fluid.

'I'he advantages of this lsystem may be sumvalve means disposed in said connections to enable the accumulator, when charged, to operate the jack under the control of the operating valve means; hydraulic actuating valve means and' a.

source ofA pressure; and piping independently connecting said accumulator and said actuating valve means with said pressure source, and said actuating valve meanswith said operating valve means; locking means for retaining said jack in a fixed position; and hydraulic fluid connections from said operating valve means to said lockt ing means for actuating said locking means, said second-named connections being independent of the ilrst-named hydraulic connections between saidvjack and said operating valve means; said Second-named connections being supplied from saidl actuating valve means, but the transmission of operating pressure through said connections to said locking means being controlled by the movement of said operating valve means.

2. A hydraulic operating system, comprising, in combination, a hydraulic jack; and accumulator adjacent said jack;` hydraulic connections enable the accumulator, when charged, to operate the jack under the control of the operating valve means: hydraulic actuating valve means and a source Lof pressure, and piping independently connecting said accumulator and said actuating valve means with said pressure source. and said actuating valve means with said operating valve means; said operating valve means comprisins controlled passageways for pressure iiuid passing from said accumulator to said jack, a valve element associated with said passageways, a valvemoving motor, and amotor chamber subject t0 fluid pressure from said actuating valve means;

locking means for retaining said jack in a xed position, a conduit leadingv from said motor chamber to said locking means, whereby said actuating valve means serves to actuate both the' operating valve means and release said locking means, and means for covering the inlet of the conduit leading from said motor chamber to said locking means, when the operating valve means Vber from said actuating valve means. REN

is idle, but which are moved to open said conduit upon the initial movement of said motor means as pressure iiuid is admitted to said'motor cham- LUCIEN. 

